6.3

Traits and Genetics

• Traits: Distinguishing characteristics that are inherited.
• Genetics: The study of biological inheritance patterns and variation in organisms.
• Gregor Mendel: Developed the groundwork for understanding genetics in the mid-1800s.
  • Observed traits inherited as discrete units.
  • Organisms inherit two copies of each discrete unit.

Mendel's Experiments

• Mendel studied plants in a monastery garden.
• Key choices in experiments:
  1. Control over breeding.
  2. Use of purebred plants.
  3. Observation of "either or" traits.

Pea Plants

• Mendel conducted experiments on pea plants.
• Pea plants reproduce quickly, and mating is easily controlled.
• Purebred plants created through self-pollination.
• Observed seven traits: pea shape, color, pod shape, color, plant height, flower color, and position.

Conclusions of Mendel's Experiments

1. Traits are inherited as discrete units.
2. Organisms inherit two copies of each gene, one from each parent.
3. Organisms donate only one copy of each gene in their gametes. The two copies segregate during gamete formation.